Sheet feeding apparatus



Nov. 29, 1966 R. E. SMITH 3,238,461

SHEET FEEDING APPARATUS Filed Dec. 28, 1964 4 Sheets-Sheet 1 FIG. I 94 RICHARD E. SMITH By MW? A T TOR IVEYS Nov. 2, 1966 Filed Dec. 28, 1964 R. E. SMITH SHEET FEEDING APPARATUS 4 Sheets-Sheet 2 M/VEA/TOR I RICHARD E. SMITH BY ATTORNEYS Nov. 29, 1966 R. E. sMlTH 3,258,461

SHEET FEEDING APPARATUS Filed Dec. 28, 1964 4 e e 5 IIIIIII'IIIIIIII! w l/Vl/E/VTOI? m3 RICHARD E. SMITH 4770 NEYS Nov. 29, 1966 R. E. SMITH SHEET FEEDING APPARATUS Filed Dec. 28, 1964 4 Sheets-Sheet 4 lli/l/E/VTOR RICHARD E. SMITH HY WW /Wp M/ hmr g/ Q ATTORNEYS 3,288,461 SHEET FEEDING APPARATUS Richard E. Smith, Webster, N.Y., assignor to Xerox gorporation, Rochester, N.Y., a corporation of New ork Filed Dec. 28, 1964, Ser. No. 421,556 4 Claims. (Cl. 271-35) This invention relates to sheet feeders and particularly to apparatus for intermittent seriatim sheet feeding of documents from the bottom of a stack.

The development of a high speed facsimile transmission has brought about the need for a reliable and simple document feeder that effectively utilizes transmission time as efliciently as possible. For this reason, it is desirable to keep the spacing between documents being copied as small as possible without interfering with the operation of the associated apparatus. It is necessary that documents of various sizes, weights, thicknesses, and surface conditions be fed to the facsimile transmitting unit individually without misfeed and without unnecessary delayed time between documents or in adjusting the feeding apparatus. It is also desirable that the apparatus be capable of feeding documents intermittently to allow for variable intervals between the documents. One of the purposes for this interval is to allow for spacing of reproduced documents on a web so that the web may be cut or severed at the receiving station. The high expense of communication facilities demands efiicient usage of transmit-ting time and as such, the spacing between documents should be as small as possible compared to the size of the documents. For the same reason, it is also desirable that there be no transmission time wasted in loading the document feeder or adding additional documents to the document feeder.

The present invention is applicable to a document feeder of the type disclosed in application Serial No. 335,293, filed January 2, 1964, in the name of Augustus W. Griswold, now Patent No. 3,239,213.

The present invention incorporates all the desirable features of top loading, bottom feeding, continuously running sheet feeders while permitting the flexibility of variably spacing and timing of sheets as required by the type of equipment with which it is associated. It is therefore the primary object of this invention to improve sheet feeding apparatus to control the timing and spacing of sheets being fed.

It is also an object of this invention to improve document feeding apparatus to allow a succession of documents to be continuously fed seriatim from the bottom of a stack with a time gap between the feeding of each docu? ment.

Still another object of this invention is to improve document feeding apparatus so that subsequent sheet feeding may be delayed without stopping the sheet feeder.

These and other objects of this invention are attained by means of apparatus for lifting a stack of documents out of contact with the feeding means thereby allowing intermittent feeding of individual sheets.

For a better understanding of the invention as well as other objects and further features thereof, reference is had to the following detailed description of the invention to be read in connection with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a document feeder incorporating the present invention and having the top cover removed and parts broken away to show internal construction.

FIG. 2 is a top view of the document feeder shown in FIGURE 1 with the side covers removed and parts broken away to show internal construction.

States Patent FIG. 3 is a side sectional view of the document feeder taken along lines 3-3 of FIGURE 2 with parts broken away to show internal construction.

FIG. 4 is a side view of the document feeder shown in FIG. 2;

FIG. 5 is a rear perspective view of the document feeder;

FIG. 6 is an enlarged detailed view of the stack lifting assembly shown in FIG. 5; and

FIG. 7 is a schematic wiring diagram showing the operation of the apparatus.

The document feeding apparatus shown in the drawings consists of a document support plate 10 adapted to hold a stack of documents at an angle to the horizontal so that they will tend to be gravity fed toward retard or separator rollers 14. The support plate 10 in the preferred embodiment, is shown inclined at an angle to the horizontal, however, the plate 10 may be in a horizontal orientation, or, in extreme cases, with the type of belt feed shown herein the plate could even be sloped away tom the retard roller to satisfy a particular application. A pair of document feed belts 12 extend through the surface of the plate 18 into contact with the bottom of the document stack and run parallel to the direction of movement of the documents. A pair of separator rollers 14 are mounted on a shaft 16 in line with the document feed belts and are adapted to rotate with a peripheral movement opposite in direction to the direction of movement :of the documents and the document feed belts.

The surface of the feed belts 12 is constructed of sponge or foam rubber, or a similar material such that the friction ,between the belt and the documents is greater than the friction between two documents. Thus, as the belts move, the friction between the belts and the document will carry the document forward. There is a strip 17 of rubber or similar material about the periphery of the separator rollers so that the friction with the documents is greater than the friction between the documents but is less than the friction between the belts and the document.

As a document is carried forward by the belts, the separator rollers force the document against the feed belts and also tend to resist the forward movement of the document and to move it back towards the document stack. Because of the greater friction between the belt and the document, the document passes beneath the separator rolls. As two or more documents are carried forward by the belt, the movement of the top sheets is impeded by the separator rollers and is held back until the bottom sheet has passed beneath the separator roller.

As the bottom sheet is advanced the leading edge of said sheet will actuate a switch 146 that de-energizes a rotary solenoid described below that in turn operates a set of fingers 142 which will lift the subsequent documents out of contact with the feed belts. As the trailing edge of the bottom document passes the switch, the fingers will drop, thereby allowing the next document to be fed. In this manner, there is a short fixed distance between the feeding of each successive document. The document support plate 10 is mounted between a pair of side frames 20 and 22. The document stack is positioned on the document support plate 10 by means of registration guides 18so that the documents are properly registered for feeding to the main machine. The registration guides 18 are sl-idably mounted in slots 30 by means of arms 28. The registration guides may be positioned across a portion of the width of the document support plate to provide side registration. The guides 18 ride across the surface of the support plate 10 and are held in position by leaf springs 38 mounted on the arms 28 and pressing on the underside of the support plate and straddling slot 30.

A portion of the document stack 41 is prevented from sliding forward towards the separator rollers 14 by means of a document retaining plate or cover 40 which extends between the side plates 20 and 22 immediately ahead of the separator rollers. A clearance or opening 42 is provided between the bottom of the retaining plate 40 and the surface of the support plate so that the bottom documents of the stack may slide beneath the retaining plate while the main body of the stack is being held in position.

Longer documents are held in place on the document support plate by means of a retractable U-shaped support member 43, which is held in mounting block 45 by means of a spring 47.

The feed belts 12, in the form of timing belts with a sponge rubber outer layer, pass around a series of pulleys 44, 46 and 48 and extend through a pair of parallel slots 50 in the surface of the document support plate 10. The pulleys 48 are mounted on a shaft 52 which is supported by a bearing block 54 secured to the underneath side of support bar 55 which extends between side plates and 22. The pulleys 48 guide the belt 12 upward through the slots 50 into contact with the document stack. A pair of lever arms 56 are supported on the shaft 52. One arm of each lever rotatably supports a stub shaft 58. The pulleys 46 are mounted on the stub shafts 58 and serve as tension pulleys for the belt 12. The other arm of the levers 56 is connected to a tensioning spring 60 so that the tensioning spring tends to rotate the lever about shaft 52 exerting tension on the .belt 12. The tensioning spring 60 is secured to adjustable tensioning arm 62 which is adjusted along guide 63 relative to top por tion 64 of the document housing by means of a screw threaded knob 65 mounted in the top portion 64.

The pulleys 44 are the drive pulleys for the belts 12 and are mounted on a shaft 66. The relative position of the pulleys 44 and the separator rollers 14 is such that the belts 12 are in extended surface contact with the periphery of the separator rollers 14. That is, the belts are deflected by the periphery of rollers 14 from a straight line path between the pulleys 48 and 44 thus providing surface contact between the separator rollers 14 and the documents on the belts 12. The shaft 66 is rotatably mounted in the side plates 20 and 22.

Adjacent to the side frames 20 and 22 are a pair of covers 82 and 84. As shown in FIG. 3, the entire document feed apparatus is supported from a counter 90 on the main machine directly in front of the feed rollers 11 by means of a pair of mounting arms 92 and 94. The mounting blocks are secured to the counter by means of bolts 96 and are shaped to support the apparatus on the counter 90 with the document support plate 10 at an angle to the horizontal, as previously described. The document is fed to the main machine under guide 12 and between the rollers 11.

The document feeder is driven by a drive wheel 98 mounted in the main machine. The drive wheel 98 drives a timing belt 103. The timing belt 103 serves to drive shaft 66 through pulley 108 and is supported by adjustable idler pulley 105. The drive pulley 98 may be replaced by separate driving means. Such an electrical motor on the document feeder can be operated independently of the main machine. Mounted on the shaft 66 is a belt drive pulley 109 which transmits power through timing belt 110 to a pulley 112 on shaft 16. The shaft 16 is essentially supported by bearing means formed inwardly with separate side frames 21 and 23. The tension on drive belt 110 is adjustable by means of a pulley 118 mounted on shaft 120. The shaft 120 is secured to side plate 23 through a slot 122 in the side frame 22 and is positionable throughout the length of the slot. By the use of the drive belt 110 shaft 16 is driven in the same direction as the shaft 66, thus causing the peripheral movement of the belts 12 and the separator rollers 14 to be in different directions.

A series of document deflectors 125, 126 and 127 are suspended from the separator roller shaft 16 and contain idler rollers 128 which ride on the document feed belts 12. The deflectors 125, 126 and 127 on the idler rollers 128 guide a document downward towards the counter as it passes by the separator rollers 14.

If for any reason a document is misfed and jams between the belt 12 and the separator rollers 14, the deflectors 126 will be deflected upwardly thereby actuating a deflector switch 134 mounted on deflector 125. This detector switch 134 is adjustably mounted on the deflector so that the amount of deflection can be varied to determine the exact allowable deflection in the deflectors 125, 126 and 127. The deflector switch 134 will be actuated when the switch arm 136 contacts block 138 mounted on top portion of the housing 140.

In operation, a stack of documents are placed on the plate 10. In the normally off position, fingers 142 mounted on shaft 144 will be in a normally raised position and the documents will not be fed into the machine. The switch 146 adjustably mounted on deflector 127 is normally closed. Upon actuation of the machine, the movement of belts 12 will commence. In addition, fingers 142 will be retracted below the surface of support plate 10 by rotary solenoid 148. The bottom-most document in the stack is then fed forward by movement of belt 12. As the bottom-most document is fed through the machine, it will contact actuator lever 147 of switch 146. Upon activation of the switch 146, the solenoid 148 will be de-energized as shown in FIG. 6, thereby lifting fingers 142 by means of a return spring built into the solenoid 148 as an integral part thereof. The actuator lever 147 is held in an electrically open position by the document in transit, thereby holding the fingers 142 upward preventing a second document from being fed into the machine. When the trailing edge of the first document passes the actuator lever 147 of switch 146, the lever 147 will return to its original position as shown in FIG. 3. The solenoid 148 will be energized thereby dropping fingers 142 below the surface of feed belts 12 allowing a second document to be fed. FIGURE 3 shows the document just as the trailing edge has allowed lever 147 to return to its original position and just before the fingers 142 are retracted to allow another document to be fed. In this manner, there is a space between the trailing edge of the first sheet and the leading edge of the second sheet. The space between documents is approximately equal to the space between the point of tangency between the conveyor belts and the retard wheels and the position of the actuating lever. It is also possible to actuate solenoid 148 by means (not shown) other than switch 146 to stop the feeding of documents. During operation additional documents may be placed on top of the stack without interrupting operation of the apparatus or disrupting the flow of documents.

While the invention has been described with reference to the structure disclosed herein, it is not confined to the details set forth, and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.

What is claimed is: 1. A sheet feeding apparatus of the type wherein sheets are fed seriatim from the bottom of a stack including support fingers positioned beneath a stack of sheets to be fed and capable of raising and lowering the stack;

sheet advancing means positioned to contact the bottom sheet of a stack of sheets on the support fingers and operative to advance the sheet contacted in the direction of feeding;

means to raise and lower the support fingers including actuating means operated by the sheets being fed;

means to retain the stack of sheets from movement in the direction of feeding;

and means to drive the advancing means.

2. A sheet feeding apparatus of the type wherein sheets are fed seriatim from the bottom of a stack including;

advancing means positioned to contact the bottom sheet of a stack of sheets and operativeto advance the bottom sheet contacted in the direction of feeding;

finger means mounted adjacent the advancing means to support a stack of sheets above the advancing means;

said finger means being movable to raise the stack out of contact with the advancing means and to lower the stack into contact with the advancing means;

means to raise and lower the finger means;

a switch positioned to be actuated by sheets fed by the advancing means and connected to control the means to raise and lower the finger means;

said switch being movable along the path of the sheets being fed to thereby vary the spacing between the sheets being fed;

means to retain the stack of sheets from movement in the direction of feeding; and,

means to drive the advancing means.

3. A sheet feeding apparatus of the type wherein sheets are fed seriatim from the bottom of a stack including:

advancing means positioned to contact the bottom sheet of a stack of sheets and operative to advance the sheet contacted in the direction of feeding;

means to support a stack of sheets above the advancing means, said support means being operable to raise the stack out of contact with the advancing means and to lower the stack into contact with the advancing the support means to allow feeding the next sheet, the distance between the sheets fed being equal to the distance between the switch and the leading edge of the stack of sheets; and,

means to drive the advancing means.

4. A sheet feeding apparatus of the type wherein sheets are fed seriatim from the bottom of a stack including:

advancing means positioned to contact the bottom sheet of a stack of sheets and operative to advance the sheet contacted in the direction of feeding;

means to support a stack of sheets above the advancing means, said support means being operable to raise the stack out of contact with the advancing means and to lower the stack into contact with advancing means;

solenoid means for operating the support means,

means to retain the stack of sheets from movement in the direction of feeding;

a switch mounted adjacent the path of the sheet advanced said switch actuated by the sheet advanced to dc-energize the solenoid means to raise support means out of contact with the advancing means thereby preventing the feeding of the next sheet, whereupon the switch will energize the solenoid when the trailing edge passes said switch thereby lowering the support means to allow feeding the next sheet, the distance between the sheets fed being equal to the distance between the switch and the leading edge of the stack of sheets;

said switch adjustably mounted to vary the distance between the stack of sheets and the switch to vary the distance between sheets fed; and,

means to drive the advancing means.

References Cited by the Examiner UNITED STATES PATENTS 12/1928 Labombarde 271-35 X 7/1932 Finfrock 271-35 9/ 1956 Weiler 271-29 X M. HENSON WOOD, JR., Primary Examiner.

J. N. ERLICH, Assistant Examiner. 

1. A SHEET FEEDING APPARATUS OF THE TYPE WHEREIN SHEETS ARE FED SERIATIM FROM THE BOTTOM OF A STACK INCLUDING SUPPORT FINGERS POSITIONED BENEATH A STACK OF SHEETS TO BE FED AND CAPABLE OF RAISING AND LOWERING THE STACK; SHEET ADVANCING MEANS POSITIONED TO CONTACT THE BOTTOM SHEET OF A STACK OF SHEETS ON THE SUPPORT FINGERS AND OPERATIVE TO ADVANCE THE SHEET CONTACTED IN THE DIRECTION OF FEEDING; MEANS TO RAISE AND LOWER THE SUPPORT FINGERS INCLUDING ACTUATING MEANS OPERATED BY THE SHEETS BEING FED; MEANS TO RETAIN THE STACK OF SHEETS FROM MOVEMENT IN THE DIRECTION OF FEEDING; AND MEANS TO DRIVE THE ADVANCING MEANS. 